Ghost Between Frames on SQA 645 back

Discussion in 'Medium Format' started by richard_rankin|2, Jul 15, 2004.

  1. Hi,

    I'm just starting to use a Bronica SQA that has been sitting around
    for about a year. While using the 645 back, I'm getting a sort
    of 'ghost image' of the frame image between frames (it sort of looks
    like the image has been stretched into the borders between frames but
    with a lighter image).

    I've tried two sorts of film, so its not the film. The development,
    etc looks fine, so I'm suspecting the back. This phenomenon does NOT
    occur on the first 3-5 frames. So, I suspect that the back is not
    winding tightly and possibly the film isn't flat as it is would up.
    If it were a light leak, it seems like all frames should be
    affected.

    Does anyone have any suggestions on what to do about this or how to
    determine the actual problem?

    Thnaks,Richard
     
  2. Off the top of my head, I would have to say that after a yr of sitting around, it probably just needs to be taken outside for some exorcise.

    Sorry... oh dear, that's punny.... ghost image.... exorcise.... thank you, thank you, try the lox.
     
  3. This sounds like the shutter was still open when the film was advanced. Were you doing any long exposures? Perhaps the shutter is sticking open. Did you advance the film just after the exposure was supposedly finished, or was there some time between clicking the shutter and cranking the film? The exposure would be stopped by winding the film, but the movement would register until the mirror came all the way down and the shutter reset. I think you'll find this is the lens screwing up, not the back!
     
  4. If you inadvertently have an AE metering prism attached, turned on, but you set the camera's exposure via the body shutter speed dial the shutter may stay open without you knowing it and perhaps do what the previous gentleman suggested.

    ie, Say the AE meter might read f8@ 2secs, and but you set manually f8 1/8 sec, you click shutter, immediately wind film, but the leaf shutter is still open at 2 secs, this may leave an image on interframe space.

    Don't ask me how I know this. Bad memories.
     
  5. I doubt the shutter sticking open is the problem if the picture itself is properly exposed. If the area within the frame is properly exposed and the only issue is that the area between frames has been exposed then the problem is probably a light leak around the frame edge in the film back. Does this happen with your 6x6 backs or only with the newly acquired 645 back? If only with the new back I suspect that the insert is not fitting properly or the back has been damaged. Load the back with a scrap roll of film. Advance a few frames so that it is tensioned properly. Remove the back and take out the darkslide. Does it appear that the film is in tight contact at the edges of the frame?
     
  6. There WAS an AE prism attached but I don't know if it was on. That sounds like the thing since I didn't set the dial on the film as it didn't go to ISO 12 anyway. I'll check this out. Thanks for all the great help.

    Richard
     
  7. paul ron

    paul ron NYC

    Perhaps the preasure plate is not making good contact or the film roll doesn't have enough tension to keep the film flat so the picture is leaking into the gutters.

    sacrifice a roll of film, advance it with out the lens on and look inside with the mirror up to see if the film is laying flat on the plate? If not you found the answer, otherwise it may be a light seal which I doubt.
     

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